Food products manufactured for public consumption are often modified by adding nutritional or other types of additives in order to enhance their nutritional properties. Nutritional fortification of food products may include additives that benefit the overall state of health of the human body. Examples of nutritional fortification include addition of vitamins, minerals, and comparable materials. These additives are either absolutely essential for human metabolism or enhance the provision of substances that may not be available in sufficient amounts in a normal diet.
In recent years, calcium fortification of foods and beverages has received significant attention. Calcium fortification and increased calcium intake is reported to be especially useful in the prevention or moderating the effects of osteoporosis. Increased dietary intake of calcium has been shown to be effective in minimizing bone loss in adults and the elderly. Moreover, increased consumption of calcium earlier in life may build reserves that enable a greater tolerance of a negative calcium balance in later years. Increased consumption of calcium, regardless of age, is expected to mitigate or delay the effects of osteoporosis. Thus, persons of all ages could benefit from increased calcium consumption. Unfortunately, many of the people in greatest need of calcium, including children, women, and the elderly, do not consume the recommended daily levels of calcium. For example, according to United States Department of Agriculture surveys, as many as nine out of ten women in the United States do not consume the recommenced levels of calcium. And the elderly often have difficulty in increasing their calcium consumption due to decreasing appetites and metabolism. In addition to bone health, recent research suggests the importance of calcium in improving colon health, weight management, and other health issues.
A large number of calcium compounds or salts have been used to fortify food products. Calcium salts which have been suggested for use or have been used as food supplements include, for example, calcium pyrophosphate, calcium hexametaphosphate, monobasic calcium phosphate, calcium glycerophosphate, tricalcium phosphate, calcium acetate, calcium ascorbate, calcium citrate, calcium citrate malate, calcium carbonate, calcium gluconate, calcium lactate, calcium lactate gluconate, calcium malate, calcium oxide, calcium hydroxide, calcium sulfate, calcium tartrate, dicalcium citrate lactate, calcium fumarate, and calcium chloride.
These calcium supplements have been used in a wide variety of food products. For example, U.S. Pat. No. 4,784,871 (Nov. 15, 1988) provided a calcium fortified yogurt. According to the patent, any calcium compound which is acid soluble could be used. U.S. Pat. No. 5,449,523 (Sep. 12, 1995) and U.S. Pat. No. 5,820,903 (Oct. 13, 1998) also provided calcium-enriched yogurts. U.S. Pat. 5,478,587 (Dec. 27, 1995) provided calcium-enriched deserts.
U.S. Pat. No. 5,834,045 (Nov. 10, 1998) provided calcium fortified acid beverages. This patent reported that the use of a calcium source comprising calcium hydroxide and calcium glycerophosphate with any acidulant will result in a beverage product having a marked improvement in storage stability. U.S. Pat. No. 5,855,936 (Jan. 5, 1999) provided a blend of calcium salts balanced with soluble and insoluble salts which are stabilized with a source of glucuronic acid. This composition is capable of fortifying milk beverages and other dairy-based products without coagulation and sedimentation, and with improved palatability. The calcium salts must be stabilized with the glucuronic acid source. Other calcium sources could optionally be included. Other calcium-enriched beverages are disclosed in, for example, U.S. Pat. No. 4,642,238 (Feb. 10, 1987; dietary and nutritionally balanced drinks); U.S. Pat. No. 4,701,329 (Oct. 20, 1987; milk); U.S. Pat. No. 4,737,375 (Apr. 12, 1988; carbonated and non-carbonated beverages containing solublized calcium and specific amounts of citric acid, malic acid, and phosphoric acid as determined from specific ternary diagrams provided therein); U.S. Pat. No. 4,740,380 (Apr. 26, 1988; soft drinks); U.S. Pat. No. 4,871,554 (Oct. 3, 1989; fruit drink); U.S. Pat. No. 4,851,243 (Jul. 25, 1989, milk); U.S. Pat. No. 4,840,814 (Jun. 20,-1989; milk); U.S. Pat. No. 4,906,482 (Mar. 6, 1990; soy milk); U.S. Pat. No. 5,397,589 (Mar. 14, 1995; milk); U.S. Pat. No. 5,690,975 (Nov. 25, 1997; fermented milk); U.S. Pat. No. 5,597,596 (Jan. 28, 1997; low pH beverage); U.S. Pat. No. 5,780,081 (Jul. 14, 1998; milk); U.S. Pat. No. 5,928,691 (Jul. 27, 1999; milk); and U.S. Pat. No. 5,897,892 (Apr. 27, 1999; milk base products).
U.S. Pat. No. 4,673,583 (Jun. 16, 1987) provided a calcium-enriched soy bean curd. U.S. Pat. No. 5,215,769 (Jun. 1, 1993) provided sauces and salad dressings containing a soluble calcium source comprising specific molar ratios of calcium citrate malate or calcium acetate. U.S. Pat. No. 5,514,387 (May 7,1996) provided calcium enriched crackers and other baked goods; an emulsifier was used to avoid adverse effect on texture and mouthfeel. U.S. Pat. No. 5,840,354 (Nov. 24, 1998) provided calcium-enriched dried fruit products. U.S. Pat. No. 5,945,144 (Aug. 31, 1999) provided a calcium fortified pasta product.
U.S. Pat. No. 5,075,499 (Dec. 24, 1991) provides dicalcium citrate-lactate for use as a calcium supplement. Tablets of dicalcium citrate-lactate were preferably taken on a daily basis. U.S. Pat. No. 6,007,852 (Dec. 28, 1999) relates to a calcium enriched natural cheese. The preferred calcium source is tricalcium phosphate. The patent indicates that other calcium sources (but does not specifically mention any specific sources) can be used so long as the calcium source forms a suspension rather than a solution in water, skim milk, or cheese milk. U.S. Pat. No. 6,106,874 (Aug. 22, 2000) provides a low pH nutritional beverage which uses pectin-free fruit juice and a calcium source selected from the group consisting of natural milk mineral concentrate, calcium lactate gluconate, and mixtures thereof.
Calcium sulfate has been found to significantly and adversely affect the organoleptic properties of food products to which it is added. Generally, added calcium sulfate results in bitterness and undesirable strong flavors with added at significant levels. See, e.g., U.S. Pat. Nos. 5,820,903 and 5,840,354. Tricalcium phosphate, although widely used, often contributes an undesirable “gritty” texture which, of course, limits the levels at which it can be incorporated in food products. See, e.g., U.S. Pat. No. 5,449,523.
Calcium enrichment or fortification can adversely affect the organoleptic properties of the food or beverage product to which it is added. Examples of such unacceptable properties include off-flavors, flavor changes, off-colors, textural changes, and the like. Some calcium compounds have more adverse effects than others, especially at higher levels of calcium addition. Thus, much of the currently available technology related to calcium addition does not provide the high levels of calcium addition desired. Further, the cost of some calcium forms is high and, thus, limits their usefulness. Thus, it is desirable to provide additional calcium compounds and/or other dietary minerals for use in food and beverage products which can provide significant levels of dietary calcium or other dietary minerals without adverse effects on organoleptic properties and at lower cost. Additionally, the form of calcium can influence absorption and use by and in the body. Additionally, the absorption of calcium can be enhanced or inhibited by other compounds. For example, some carbohydrates can improve calcium absorption. Greger, “Nondigestible Carbohydrates and Mineral Bioavailability,” J. Nutr., 129, 1434S-1435S (1999); Weaver, “Calcium in Food Fortification Strategies,” Internat. Dairy J., 8, 443-449 (1998); Brommage et al., “Intestinal Calcium Absorption in Rats Is Stimulated by Dietary Lactulose and Other Resistant Sugars,” J. Nutr., 123, 2186-2194 (1993).
Lactobionic acid (4-O-β-D-galactopyranosyl-D-gluconic acid; CAS Reg. No. 96-82-2) is a water soluble, white crystalline compound. It can be synthesized from lactose by oxidation of the free aldehyde group in lactose as carried out catalytically, chemically, electrolytically, or enzymatically. Harju, Bulletin of the IDF 289, ch. 6., pp. 27-30, 1993; Satory et al., Biotechnology Letters 19 (12) 1205-08, 1997. The use of lactobionic acid or its salts as additives in food products previously has been suggested for several specific applications. Calcium or iron chelate forms of lactobionic acid has been described for dietary mineral supplementation. Riviera et al., Amer. J. Clin. Nutr.; 36 (6) 1162-69,1982. U.S. Pat. No. 5,851,578 describes a clear beverage having a non-gel forming fiber, and water soluble salts of calcium, with or without water soluble vitamins, with or without additional mineral salt supplements and buffered with food acids. The food acid buffering agent includes citric, lactic, maleic, adipic, succinic, acetic, acetic gluconic, lactobionic, ascorbic, pyruvic, and phosphoric acids, as well as combinations thereof. Calcium lactobionate, a salt form of lactobionic acid., has been approved for use as a firming agent in dry pudding mixes. 21 C.F.R. §172.720 (1999). Also, the possible use of lactobionic acid as a general food acidulant has been proposed, albeit without exploration or illustration. Timmermans, Whey: Proceedings of the 2nd Intl Whey Conf, Int'l Dairy Federation, Chicago, October 1997, pp. 233, 249. This article generally describes lactobionic acid as being useful as an antibiotics carrier, an organ transplant preservative, mineral supplement, growth promoter of bifidobacteria, or as a co-builder in detergents in its potassium salt form. More recently, the use of lactobionic acid in cheese and other dairy products has been described in copending U.S. patent application Ser. No. PCT US02/14337, filed May 7, 2002, (International Publication WO 02/089592) which is owned by the same assignee as the present application and which is hereby incorporated by reference.
The present invention provides mineral complexes of lactobionic acid which are very effective as mineral fortification agents and which do not significantly affect the organoleptic or textural properties of the food or beverage to which they are added. Such mineral complexes can be produced in a cost effective manner from inexpensive starting materials such as lactose or whey.